Sarah Marywrote a review of Arc'teryx Beta AR Pant - Women's on January 22, 2018
Familiarity: I've used it several times
Fit: Runs small
I bought these pants for Mount Kilimanjaro as well as general winter hiking and snowshoeing. They kept me dry and warm during a hail storm which turned into a snowstorm at 15,000 feet as well as on a very snowy & icy summit day at nearly 20,000 feet.
Although fitted through the hip, these pants fit easily over a pair of Columbia Heat Tech leggings and also over a pair of heavier, climbing weight base leggings; you can cinch at the waist with the built in belt. I do find Arcteryx to run small, so I got a large, and just belted tight. What I liked about these pants was the built in gaiter, which easily hooked onto my boot laces and kept out all of the icy scree. It was roomy enough too that I could wear over my existing gaiters too for the really bad summit weather. I also really liked the side zippers, which were great for ventilation and heat control. There is a good solid pocket, which fit my small digital camera & chapstick.
They dried easily and I was able to just wipe off the mud.
They are packable and I did fit into a stuff stack but my larger sized one, as they do not pack down small due to the gaiter and reinforced inner leg. I found it easier to fold in half and then half again, rather than roll.
I do recommend sizing your current size or even sizing up - as I did find the pant to be a bit fitted in the thigh and quad - especially if wearing a heavier baselayer. I sized up as I was between sizes and I am glad I did as I did not have any issues with mobility.
Have since used on a winter hike and am planning on turning them into my ski pant. Really happy with this purchase and although pricey, they seem like they will last forever. A great all around mountaineering pant!